http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
In-Mold Rheology 평가를 통한 분말사출성형공정 최적화
장진만(Jin Man Jang),차범하(Bermha Cha),서정식(Jungsik Seo),고세현(Se-Hyun Ko),손성호(Seong Ho Son),이원식(Wonsik Lee),나영상(Young-Sang Na) 한국생산제조학회 2011 한국생산제조시스템학회 학술발표대회 논문집 Vol.2011 No.4
두 종류의 피드스톡과 몰드를 이용하여 각각의 몰드에 대한 In-mold Rheology 곡선을 산출하였으며, 이를 통해 rheology거동을 변화시키는 요인에는 피드스톡의 물리적 특성(점도) 뿐 아니라 몰드의 형상 및 크기 또한 포함이 됨을 확인하였다. Rheology평가를 통해 설정된 최적의 사출속도가 사출 성형체와 소결체에 미치는 영향을 관찰한 결과 전체적인 형상 및 크기는 유사하게 나타나는 반면 가장자리 부분의 예리함과 조직의 차이를 나타내었다.
Space holder 공정으로 제조된 치과 임플란트용 타이타늄 다공체의 파손 분석
이승미(Seung-Mi Lee),장진만(Jin-Man Jang),이원식(Won-Sik Lee),변재원(Jai-Won Byeon) 한국신뢰성학회 2016 신뢰성응용연구 Vol.16 No.2
Purpose: The purpose of this study is to analyze fracture behavior and failure mechanism of porous titanium for dental implant fabricated by space holder process. Method: Three porous titanium specimens with a specific volume fraction of open pore were test by 3 point bending and compression stress condition, respectively. Fracture appearance was observed by scanning electron microscope and discussed in relation with oxygen content. Results: For compression-tested specimens, two specimen showed brittle failure, while the other one showed normal failure after deformation. High oxygen content was detected in the brittle-fractured specimen. Several micro-cracks initiated at the struts propagated down to the bottom of the specimen resulting in normal failure. Conclusion: Oxygen contamination during the fabrication process can leads brittle premature failure, and hence quality problem of the porous titanium for dental implant.
차범하(Bermha Cha),장진만(Jin Man Jang),서정식(Jungsik Seo),고세현(Se-Hyun Ko),손성호(Seong Ho Son),이원식(Wonsik Lee),유우경(Woo Kyung You),이재성(Jai-Sung Lee) 한국생산제조학회 2011 한국생산제조시스템학회 학술발표대회 논문집 Vol.2011 No.4
재활용된 티타늄 수소화물 분말을 사용하여 피드스톡을 제조하고, 이를 이용하여 사출성형공정 조건을 최적화 하였다. 원료분말은 Ti chip의 재활용 공정을 통해 제조된 평균 350nm 크기의 분말을 사용하였으며, 피드스톡 제조 시 최적 분말 고상율은 68%였다. 제조된 피드스톡은 2000Pa.s 이하의 점도를 나타냈으며, 최적의 사출조건으로 미세한 부분까지 건전하게 성형된 사출체를 제조하였다. 또한 피드스톡의 열분석 결과를 이용하여 탈지 및 탈수소화 공정의 최적화를 이루었으며, 고진공하에서 소결 시 완전치밀화를 얻을 수 있었다.
MA법으로 제조된 Ni기 합금에서 Y<sub>2</sub>O<sub>3</sub> 첨가에 따른 인장강도변화와 시효처리 효과
김일호,이원식,고세현,장진만,권숙인,Kim, Il-Ho,Lee, Won-Sik,Ko, Se-Hyun,Jang, Jin-Man,Kwun, Sook-In 한국분말야금학회 2008 한국분말재료학회지 (KPMI) Vol.15 No.1
Ni-20Cr-20Fe-5Nb alloy with or without $Y_2O_3$ was manufactured by mechanical alloying process and consolidated by spark plasma sintering (SPS). The grain size of the alloy with $Y_2O_3$ was smaller than that of alloy without $Y_2O_3$ which results from the effect of $Y_2O_3$ suppressing grain growth. The tensile strength at room temperature was increased by the addition of $Y_2O_3$ but decreased abruptly at temperature above $600^{\circ}C$. It seems to result from the change of deformation mechanism due to fine grain size, that is, grain boundary sliding is predominant at above $600^{\circ}C$ while internal dislocation movement is predominant at below $600^{\circ}C$. After conventional heat treatment process of solution treatment and aging, a small amount of ${\delta}(Ni_3Nb)$ phase was formed in Ni-20Cr-20Fe-5Nb alloy while a large amount of ${\gamma}"(Ni_3Nb)$ was formed in Inconel 718 in the previous report. This is due to exhaustion of Nb content by the formation of NbC during consolidation.
임동화(Dong-Hwa Lim),장진만(Jin-Man Jang),최종수(Jong-Soo Choi),이은석(Eun-Seok Lee),김진한(Jin-Han Kim) 한국항공우주학회 2007 韓國航空宇宙學會誌 Vol.35 No.2
액체 추진 로켓을 구동하는 충동형 터빈은 크기가 작고 가벼워야 하며 큰 출력을 발생시켜야 한다. 충동형 터빈은 초음속 조건에서 작동되기 때문에 유동 특성이 매우 복잡하여 성능 예측은 주로 수치해석에 의존해 왔다. 그러나 신뢰성을 확보하기 위하여는 해석결과를 실험으로 검증하는 과정이 필요하다. 본 연구에서는 설계에 사용되는 주요 변수들의 영향을 확인하기 위하여 회전하는 3차원 축류 터빈을 2차원 형상으로 모사하여 실험 하였다. 먼저 노즐 출구에서의 마하수를 측정하였으며, 이론적인 노즐 추력식을 유도하여 터빈 블레이드에 작용하는 깃하중을 계산하였고 측정된 결과와 비교하였다. 또한 추력 계수를 구하고 이를 통해 터빈 출력을 예측하여 설계 요구 조건의 타당성을 확인하였다. An impulse turbine, which is a main component of a liquid rocket engine, needs to be a small size with light weight and generate large power. Since the impulse turbine is being operated under complicated supersonic conditions, flow analysis and performance prediction largely depend on CFD technique. In order to increase the reliability of the prediction code, however, it often requires an experimental data to compare. In this research a rotating turbine rotor with multiple blades is simulated with a two-dimensional stationary cascade to check the effect of major flow parameters. Mach number is measured at nozzle exit by using a pitot tube and the blade thrust was also measured with a load cell. The measured thrust coefficient and the power are compared well with the designed conditions, which proves the design procedures are properly taken.
김덕호(Duk-Ho Kim),박노철(No-Cheol Park),박종범(Jong-Beom Park),이상정(Sang-Jeong Lee),장진만(Jin-Man Jang) 한국소음진동공학회 2016 한국소음진동공학회 학술대회논문집 Vol.2016 No.4
Recently, As an advanced technology is applied to the vehicle, a smoother driving with less vibration and noise is desired. As a result, the structure-borne noise of the vehicle becomes important in the vehicle industry because the reduction of the structure-borne noise improves the stability of vehicle. The structure-borne noise takes place when excitation force of tire passes the vehicle structure such as front suspension, rear suspension, chassis, body. Its range is commonly from 0 Hz to 500 Hz. In order to reduce the structure-borne noise of the vehicle, we need to analyze the dynamic characteristics of the front suspension which is one of the major course of the structure-borne noise. So we practice a modal experiment and a modal analysis with regard to the components of the front suspension. Finally, we confirm the dynamic characteristics of the components of the vehicle front suspension such as knuckle, disk, lower arm, bearing, strut – damper in this paper. These results are significantly useful to get the analysis models which are small part of the front suspension and proceed the transient analysis of the whole front suspension.
다양한 형상을 갖는 알루미늄 발포금속 충진 튜브의 에너지 흡수능
장진만,이원식,고세현 대한금속재료학회 2005 대한금속·재료학회지 Vol.43 No.4
In this study various types of Al foam filled tubes were fabricated using foam of A1-12wt%Si by powder metallurgical process. Their energy absorbing efficiencies were investigated with compression test, focusing on the structure and bonding effects between tube and foam. The results show that the energy absorption is affected by structure of Al foam filled tube. Among fully foam filled tube, partially foam filled tube and Al hollow tube with the same weight, fully foam filled tube seems to have superior potential for industrial application to energy absorption parts. Also energy absorption efficiency is increased by interaction between tube and foam and especially, bonding between tube and metallic foam gives rise to increase the energy absorption efficiency up to above 1.2 times. This results from the arrest of folding of tube by metallic foam and the change of stress mode from uni-axial to multi-axial during compression. (Received September 30, 2004)